SYNDROMES OF THE PONTILE TEGMENTUM

Abstract

The pons is divided dorsoventrally into three portions, the tegmentum lying in the center, with the basis situated ventrally and the tectum dorsally. Each portion has certain syndromes connected with it, although there is not uncommonly some overlapping. Most present knowledge concerning the various structures in the pons has come from clinicopathologic studies, reaching back at least eighty years. Briefly considered, the syndrome of the basis is predominantly motor, since the pyramidal tracts are located ventrally. Unilateral lesions, occurring in response to thrombosis of small branches of the basilar artery, are by no means infrequent in cases of cerebral ateriosclerosis, but are seldom large enough to produce a severe degree of hemiplegia. Sometimes such a lesion can be recognized by the great degree of spasticity without involvement of sensibility or language. Bilateral lesions of the base of the pons are a frequent cause of pseudobulbar palsy.¹ Much of the